Quick-detachable combined dust and air cap for valve-stems



J. M. McNAMARA. QUICK DETACHABLE COMBINED DUST AND AER CAP FOR VALVE STEMS.

. APPLICATION FILED OCT 2. 1919.

Patented Feb. 17, 1920 i wu @rri w 1 ll ninth siftti-hltEx sinsists,

Refill Glilllliifl Speeirlcaticn of Letters Patented J Application filed October 2, 1919. Serial No. 327,893.

To all whom it may concern:

Be it known that I, J osnrn' M. MGNAMARA, a citizen or" the United States of America, residing at Clinton, in the county of Worcester and State of Massachusetts, have invented certain new and useful Improvements in Quicl:-Detach-nble Combined Dust and Air Caps for Valve-Stems, of which the followingis a specification.

This invention relates to improvements in quick detz'icha'ble combined dust and air caps for valve stems, and more particularly to improvements in that class of valve stem caps which are used in connection with pneumatic tires, such as automobile tires, the object 01"- the invention being to provide a combined dust and air cap for such valve stems which can be placed on the stem and very easily, quickly and firmly locked thereon against displacement, without the necessity of screwing the cap for the entire length of the stem, and by means oi? which the time consumed in removing am replacing the cap is reduced to a mere traction of the time necessary to perform this function with the commonly 1 '"cd dust and air caps.

In the drawings 2H; ompanying and formingpart oi this specification,

Figure l. is a side elevation, partly broken away, of a portion of a telly of a wheel showing my improved valve stem cap applied thereto, he cap being shown in section,

Fig. 2 is a transverse sectional view taken substantially upon line ll H of Fig. l,

3 is a. transverse sectional view taken substantially upon line lll-lll of Fig. 1,

4. ig. a bottom plan view of the dust cap with the air cup and spring removed,

Fig. 5 is a view similar to l with the air cap in position for insertion within the dust cup,

Fig. 6 shows the air cap in side and edge views, and s Fig. '7 is an elevational view of the spring for seating the air cap and preventing accidental displacement of the dust cap.

Similar reference characters indicate corresponding parts throughout the several ures of the drawings.

. Practically all valve stems now in use for inner tubes of automobile tires are flattened on two sides and threaded to a standard diameter and pitch for a. greater portion oi their length, and the dust caps are threaded to the same pitch and screwed on such stems substantially for the entire length of the stern which projects through the telly or" the wheel. Moreover, the free end portions these valve stems are reduced and threaded to a. standard diameter and pitch, and small air caps are threaded onto these threaded portions of the stem 7 against leakage in case the valve wi stem should leak. Obviously, con time is consumed in first remodust caps and then removing the air for such purposes as inflating the tire, lil e. The present invention, which 0. provide means for simultaneonsly cite, closing the free end oi the valve sti protecting the valve stem from d1 expeditious manner, compriss a dust cs which is threaded only :it one portion of i length, as for instanceits on" 11 end, (is at 6, and these threads do not extend the entire inner wall of the borrot i I but are broken away at opposite pm 10! as shown at 7, Figs. and l. correspondingz to the threaded portions 8 of the valve stem 9. The purpose of thus forming the threads i in the bore of the cap is to enable the he slid over the stem as far as rcquii out the necessity of screwing or unsc said cup, and by a single turn or if the cup to bring its threads into one with the threads on the stem to thc rain the cap on such stem. Due tion set up between the abuttin telly l0 and the washer ll Wl carried at the open end o latter is additionally hel An air cap 12 is lora' cap 5 for l and, although this air preferred construction. illustrated as formed of shell having a rubber therein, the exposed edge being yieldingly pressed with the adjacent free end 9 by means of the clearly shown in Fig. 1. In order to pro vide for renewal of the air cap 12, said air cap is provided with flattened sides as at 1-3 so as to permit ready insertion thereof into the dust cap 5 when disposed as shown in Fig. 5 and when given a quarter of a turn to assume a position in the path of the threads 6, at which time said air cap 12 is prevented from displacement outwardly of the dust cap 5.' In assembling the present device, the spring 1% is inserted previous to into engagement of the valve stem 10o helical spring l'L-t the insertion of the air cap 12, and said spring-14 is of such length as to cause engagement of the air cap 12 with the adjacent end of the valve stem 9 before the dust cap 5 has been placed all of the way on said valve stem. Spring resistance is thus offered t the final movement of the dust cap onto the valve stem, so that when said dust 3 cap is given the single turn or twist herein- :upa friction between the threads 6 and 8 so as to doubly insu-r'e'against accidental displacement of the caps off of the valve stem.

beforementioned, the spring 14 acts to set The cap may be provided with wings 15 to be engaged by the fingers in turning the same, and the usual tire valve tool 16 may be formed on the closed end of the dust cap 5 instead of on the'air cap as has been the shown and described is what is believed to bethe preferable embodiment thereof it is nevertheless to be understood that minor changes maybe made in the form, com-bination, and arrangement of parts without departing from the spirit and'scope of the invention as claimed.

What I claim is The combination with a valve stem havng a mutilated thread, and a dust cap longer than the projecting portion of said stem and having a mutilated interionthread, of an aircap slidably disposed 'Within's'aid dust cap, and a spring within the dust cap for yieldingly pressing the air cap into engagement withthe free end of said valve stem prior to the final movement of the dust cap on such stem, said air cap ibeing provided with flattened sides whereby the same may be inserted in the dust cap, and when turned, retained in said dust cap by means of said mutilated interior thread of the dust cap.

JOSEPH M. MONAMARA.

In testimony WhereofI aflix my signature. I 

